Measuring apparatus for gauge determination of dimensions of bodies with flow of fluid under pressure from an orifice



July 4, 1950 c. STEAD ETAL 2,513,374

MEASURING APPARATUS FOR GAUGE DETERMINATION OF DIMENSIONS OF BODIES WITH FLOW OF FLUID UNDER PRESSURE FROM AN oRIFI-cE Filed Jan. '7, 1948 4 Sheets-Sheet 1 l Tlql.

IN V EN TORS y 4, 1950 c. STEAD ETAL 2,513,374

' MEASURING APPARATUS FOR GAUGE DETERMINATION OF DIMENSIONS OF BODIES WITH FLOW 0F FLUID UNDER PRESSURE FROM AN ORIFICE Filed Jan. '7, 1948 4 Sheets-Sheet 2 IN V EN TORS Walom, flaw VIM y 1950 c. STEAD ETAL MEASURING APPARATUS FOR GAUGE DETERMINATION OF DIMENSIONS OF BODIES WITH FLOW 0F FLUID UNDER PRESSURE FROM AN ORIFICE 4 Sheets-Sheet 4 Filed Jan. 7, 1948 Patented July 4, 1950 MEASURING. APPARATUSFOR GAUGE DE- TERMINATION OF DIMENSIONS OF BODIES -WI-TH FLOW OF- FLUID UNDER PRESSURE FROM AN ORI'FICE Clifford. Stead, @Bellingham, ,Mass, ,and Franklin Meyer, Jr., Philadelphia,.Pa., a'ssignorsto' The Taft-Pierce Manufacturing Gompany, *Woonsocket; R; 1., a corporation-'of 'Rhode Island Application January 7, 1948, Serial No. 892

4"Claims.

The. presentinvention relates to measuring apparatus vfor. gage determination ofdimensions of bodieswith .outlet flow. of fluid under pressure from anozzle orifice wherein the rateofoutlet fiowis governedlby a certain. dimension of .the

'. body. being gaged.

. Ageneral object ofthepresent inventionis to provide measuringv apparatus of the indicated type which is of simpleconstruction but highly sensitive to velocity variation and capable of precision operation forefiicient gage determination-of dimensions of bodies .by comparison with those of-a master or standard part or parts and which, by efiective magnification, permits accurate and ready, determination by meter readings of very small variations in dimensions; embodiments 1 preferably being constructed to assure read-y adjustment byv simple manipulation to bring v the. indicator of the. ,meter to a reference or .zerosetting for use of, the device withv-varyingjkinds of gaging nozzle means or. members adapted respectively to the measurement of various dimensions of different body parts.

A more specificobj ect of the present invention is .the provision in such. fluid ,gage apparatu .of Venturi means which will provide 1 differential fluid pressure for .efficient operation of gagemeter means-withflowof fluids, such as air under .pressure, to'the gaging nozzle imeans, and so equipped nastopermit by manual manipulation. of a bleed valve adjustment of the rate. of venting part .of

the fluid or air from .theVenturi means, t0..at- .mospheret adjust themeter to zero. setting :for: any particular comparative-measurement of dimensions of. certainparts of particular bodies.

- Another fobjectofthe ,present. invention is to providesuch a structure inthe form of a selfcontained apparatus unit or instrument equipped with a supply-conduit. preferably of-the flexible tube type, avisual dial. meter, aquick-change fitting;for connection toanyone of aplurality of gaging nozzle means or members and at least .one manual. control .orlmob for adjustment of rdeviceqandcomponent. parts. thereof which are readily constructed and permits eflicient use and operation. thereof.

Other objects of-theinvention will. in part be obvious andwill in part appear hereinafter.

The invention accordingly comprises. the feaetures: vof; construction, combination of. elements and arrangement of parts, which will be; exemplifiedin'. the construction hereinafter set forth; and the scope'of the invention Will'jb indicated in the claims. i

For a' fuller understanding of the nature and objects iof'the invention, referencesheuld 'be had to the" following detailed" description taken-in connection with the accompanying drawings,- in

which:

1 shows in'diagrammatic form, with parts iii-section; a-layout-of an embodiment of'tlie-presentinvention;

Fig. 2 is an elevational view with parts-in section, of a -m'odified form of di iferential-pressure gage meter meansof the '-apparatusshown in Fig, 1;

Fig: 3-' is a perspective view of i a preferred, self "containedfin'strumentembodiment-ot gage' apparatus-of-the present invention;

Fig. 4* is a side--elevational view to a larger scale, "withparts brokenaway and insection, of the apparatus shown im'Fig. -3;

Fig. 5 is-a-top planview,=with-parts br0ken away and insectiong=-ofthe apparatus shown in Fig.

' Fig: 6-is -a sectional view, to an en-larged scale, taken substantiallypn line 6 -6 of; Fig: 4

Fig. '7 is a sectional "viewto the same-scale of "Fig: fiytaken, substantially on line l1 of Fig. 4;

3o w away; taken substantially on line-8 -8'o-f-Fig; 12,

Fig. 8 is a sectional view,-with-'- parts broken but to a larger scale;

Fig. 9-is a' front viewgto an enIarged-scaIe, of the face of the meter and associated structure exposed-onthe front of the "apparatus shown in'Figs; 3,4 an'd'5 "Fig, 10-is a sectional view takensubstantially Fig. 11 is asectionalview; toan'enlarg'edscale, takensubstantiallyon line ll I of -Fig.-9; and Fig. 12 is a'rear end-view, with parts-omitted,

. of the meterunit shownin Fig. 11, but toa reduced scale;

'Referringito the drawings, like-'numeralsidentifyisimilar parts'throughout and-as will be seen "of fluid'under pressure, such as compressed air.

Supply conduit 20 is connected to and" communicates withthe-interionof suitable pressure regulator means '21-; which may ,be' equipped, as

able filtering; materialfor screening out oil or moisture that may be suspended in the supplied compressed air. The air, preferably after being filtered, passes through any suitable regulator mechanism at 23 which may be of known construction (not shown) and provided with a suitable manual adjusting knob 24. Conduit means 25 feeds the compressed air, after passing through regulator mechanism 23, to a suitable Venturi conduit means or unit 26.

The Venturi conduit means 26 may comprise a body or block 21 having a through bore 28 capped off at one end by a cap screw or threaded plug 29 and closed ofi at the other end by bleed valve 30. The passage provided by the bore 28 is stepped or counterbored to provide a Venturi constriction at 3| and another at 32, with the latter preferably, but not necessarily, being the one of smaller diameter. When the Venturi constriction of smaller diameter is arranged on the downstream side ofthe larger constriction possibility of difiiculties due to turbulence, etc. is avoided. The portion of the passage 28'ahead or upstream of the first Venturi constriction 3| is brought into communication with the supply conduit 25 through a bore or hole 33 to constitute an inlet for the Venturi means. Portion 34 of passage 28 between the smaller Venturi constriction 32 and the bleed valve 30 constitutes an outlet space or chamber and is connected by an outlet bore or hole 35 to duct means ora conduit 36 leading to any suitable gaging nozzle means or member 31.

As shown in Fig. 1, the gaging nozzle means or member 31 may be provided in a form suitable for rapid and repeated comparison of the internal diameters of rings, such as that shown at 38. For this purpose, the gaging nozzle means may comprise a body 39 having a longitudinally extending bore 40 communicating at one end with the duct or conduit 36 and at the other end with a cross bore 4| terminating at the sides in nozzle tips 42, 42, each having an orifice feeding to a localized surrounding depression 43. As

- otally-mounted rocker shaft 59.

---shaft 59 may also carry fixed thereto another radially extending pin 60 against which bears the head of a T-pin 6| reciprocatively mounted through a hole. in the casing 50 with its inner end fixed at 52 to the head of the diaphragm element 41. g

understood in the art, a greater number of the cross bores and nozzles may be provided to assure distribution of many air jets circumferentially about the gaging head 39. The depressions 4 3, 43 are relieved by longitudinally-extending It will be noted that the pointer-operating mechanism of the meter proper is mounted exteriorly of or excluded from the pressure chambers provided by hollow diaphragm 41 and closed casing 50, as contrasted with prior practice of locating and sealing such mechanism in one of the chambers. This exclusion permits provision of both of the pressure chambers in minimum volume so that the pressure spaces on both sides of the diaphragm may be made of substantially equal fluid capacity, even when a hollow diaphragm of the type indicated is employed. That equalizin of the pressure spaces has been found in practice to give unusual high speed response and attendant accuracy.

The bleed valve 30 ,may be of any suitable or known construction, such as a needle valve structure. Bleed valve 33 may include an internally-threaded sleeve B3 ha ving a reduced, externally-threaded end portion 64 threaded into the outlet end of the through bore or passage 28 and provided with an internal valve seat at 65. A needle valve 65 for cooperation with the valve seat 65 has an externally-threaded portion 6! to be threaded into the internallythreaded sleeve 63 and carries a manual operating knob 38. Beyond the valve seat 65 the sleeve 63 has an outlet hole at 69 for venting air to atmosphere.

In use of the device shown in Fig. 1, operation is initiated by supplying from supply conduit 24 compressed air at a controlled pressure (regulated by the regulator knob 24 as it passes from the supply conduit 20 through regulator mechanism 23) through conduit-25 to the Venturi body grooves 44 for ready passage of the discharged fluid or compressed air to atmosphere after gaging has been accomplished in the clearance between the nozzle tips 42, 42 and the inner cylindrical surface of ring 38.

The larger Venturi constriction at 3| is condifferential pressure gage meter means, and ity is possible, if desired, to reverse the ducts 4t and 49 with respect to their connections to hollow diaphragm 41 and its casing 50, it merely being necessary to subject the diaphragm to the differential in pressure between the Venturi constrictions.

That meter means circular dial face 5! having indicia or scale divimay be provided with a Isions-for indicating dimensions in fractions of inches or other standard units. An indicator arm or pointer 52 is pivotally mounted at 53 for sweep or unit 26 which, together with the meter means, constitutes a metering device. The compressed air then passes on through conduit 35 to the gaging nozzle means or member 31 from the nozzle tips 42, 42 of which it is discharged to atmosphere. Dimensional readings of body parts, such as the internal diameters of a plurality of rings '38 are obtained by covering the gaging nozzle tips 42, 42 with the part to be measured, with the result that the nozzle orifices in the gaging member have the fiow of air therefrom restricted to a certain extent.

Of course, it will be understood that the gaging member can be made in many known different forms, such as a plug, ring, or snap gage or a nozzle having a single outlet arranged above an anvil, etc, and such gaging member can be used for measuring internal diameters, as proposed in Fig. 1, or external diameters, Width, thickness, concentricity, length, or any type of gaging that is usually obtained by some mechanical contact indicator.

Since this fluid gageapparatus isof the comparator type,'it is'understood that some type of master or standard part or parts is or are to be first used forsetting' the working range of the meter, and thereafter the parts to be gaged Off "this'r'gaging "apparatus: measures change in Velocity that 'resu ltsdromthe restriction of -the air iiow hy' thepart beingfgagfed, (The-resultin velocity of 'the" ai r which "'p'assjes fromthe nozzle means to atmosphere will bedetermined by the clearance between the gaging memberat-"the nozzle orifices and theopposed "surface of the .i f e a n .1 16 i c an fie P e ics in the?" m hange'f of ve'locity icated bythe-m'eter will represent; a "size change fini the" part: with t inuic'ia-o A t ey-mete dial showing "linear dimensions.

v operation thef ap paratus "of Figfh the fi erect and" pr pre -regulated} working fluid or I flowsf' at constant '-'pres'sure threu'gh the inle bore tt in-the-Venturi' -block Z6 andtheneevia the inlet/ of passage zfifthrough the; larger Venturi "sectioir' or fir'st constriction at' 3 l at increased velocity, Compressed air then qwl f ei e r i S ct on? or constriction, through t e m ier venturi' 'sectionor-constrictio'n*at"-3'2- atstillhigher-'yelocityto-the out-- let space or chamber 34 and fromthe latter, via

and' orifices' ofnozzle tips "42 42; in the gaging head or member 31, where it is permitted to flow maths "opposedsurface of the part being gaged,

such" as the internal cylindrical surface of ring 38 and-thence to the atmosphere through relief passages 44-344. 1

Pl'iysical' laws-dictate that the total energy disregarding minorlosses, mustbe the same at both Venturi constrictions 3l-'=an'd "32 and the di flerentwelociti'es thereatare proportional to the cross-"scanner areas of those sections.

Thusythese'ctio'n' having the 1arger-'cross-sec and the" lower Velocity.

' will 'varyfinproportion' to the velocities of the 'andBZ; with thepressure inside the diaphragm v IT-being "greater" than the pressure exteriorly ai r -fiow-and the cross-sectional areas of the Ventur'i"constrictions 3| andti. When the orifices of nozzle ti s-"42, 42 are completely -uncovered, the velocity'of air-flow is-high and this W iIYciate a relatively high differential in pressure between'thetwo' Venturi constrictions 3i thereof w'ithinthe casing 50. As a result,"diaphr'a'gml'l willexpand until thepressure in the chambeninappliedto the exterior of the'diaphraig'inandthe recovery force of the diaphragm spring materialtoget her balance the pressure within-*thediaphragm. -Resultant motion of the noz zle -hea"d or member't'l, the velocityof air tl ie r'i decreased 'byvirtue of f the p 'rs'tiictibr'r'produced b'y' the internal surfaces "of -75' the'meterpointer. Thepresent"invntionmakes Thus, the" sure in' the" diaphragmthe-la tter contracts until "a" new 3 balance *'of*'forcesf-isobtained. This-ponftractionYof thediaphragm-retracts the-T--p'i-ri 6| "to-move the-meter pointers: to-a new reading on the-dial for purposes of lcoinparisoni the new 10 reading-being} direct indication or adifference between the-"- d-iniensionofthe body being gaged anda nias'tenorfstandard --bo'dyor" part initially "'einployed for 'obtain ing -areference readingf'or setting tl'ie ifieter of -the--apparatus llVithprovision of accurate-proportions betweenthe crosss'ectional areas o'fthe Venturi constrictions l at fi l and 32, the cross sectional' areas-of the no'zzle orifices 42. in=gaging head '31 and the total-clearance between the surfaces of thegaging orifices 1 and the opposed-surface of the body-being gaged, f such as the cylindrical surface oi the :holein ring .-38,':=small changes in that -total clearancewwill create corresponding changes in the pressure "differential which is applied to the metendia- 2'5 :phragm 4] .withia resultingsgreat magnification of :the size change. The apparatus highly am- --plifi es-.in :an efficient manner veryminute differences *in dimensions of parts being gaged. .The velocity" indication=will always be the same forany particular: gaging=conditions and, thus, this apparatus; ives excellent, repeatability..

, In practice it- -is: frequently; desirable, to employ twomaster parts, one dictatingathemaximum c eptab s ze. r. versi e tol rance f dimension reate than iven pec fic and. the vother dictat n the mi imum. cce t ble sizev enumersize q rance f dim ns on ,less.,th n... hei ive pec c, B o e. gaging f 'a a ty, ii 10- u i n arts l r e di ss, an b ken-wi to the use of both rnaster parts to indiicate on the 1. dial, t e. imits,ei,.. e\; q p Size rt lera ra ge. Th ea ter in e odu tion, parts all those which show inet er'readings Within that Tde'nned dial'r'an'ge areacceptable with those givfin'g" readingoutside" that raflge'being rejected. The r'eadii igs ohtain'edby such employment "or master parts maybe considered "to "be" reference readingsaridlwh'enofrily one'ma'ster part is empmysto "g'ivepn'ly"one'ieference reading as 501 a'gi'i'IZen spacific z'ero' stting'ofthe'mete'r will Tb o'r'i'sidered'to' be'atta'ined' whenbperation' or adjustment 'of"the"meterfhrings or shifts that referenceireading intoc'oirrcidence with a" desired p'oint'oii thef'di'al, "such asthe' zero indicia or "mark. "When two 'rm'asterparts are employed to define an" acceptable size or' tolerance range zero--"setting will i be attained when operation or adjustment-of the meter brings or shifts those two reference readings-defining the limits of thatrange' intoboincidence with two points-on the dial selected'as desirable for indicating the range limits, i. e. shifts the indicated range to the desiredor-most [convenient section orsector ofthe'dial. I

"It isnow seen-that, for efficient use of meter readings of the apparatus and to assure that the dial pointer will be disposed or positioned. in a convenient reading range, it is highly-advantageous that, for any given set of conditions with the use of any particular gaging head or member for comparison determination of dimensions of any particular part of a certain type of body, there be provided simple and readily operated adjustment means for attaining zerofsettirig of such provision in equipping the apparatus with the manual-bleed valve at 30. When the apparatus is provided with a certain type of gagmeter pointer 52 is disposed opposite a desired point or the zero indicia on meter dial If two master parts are used to define a size range both may be successively applied first to determine the dial range before manipulation of bleed valve knob 68 to dispose that range overthe desiredonmost convenientsection or sector of the dial. This venting; increases the total amount of air flowing with some escape through the bleed valve to atmosphere without passing through the gaging-head. Since this vented air is not metered between surfaces of the nozzle head and opposed surfaces of the part or body,

it does not materially change the calibration range of the meter, but provides a means of shifting the; pointer to the desired position on the dial. After such zero setting of the meter, the parts or bodies which are to be comparatively dimensioned are then successively applied to the nozzle head. Movement of the pointer in one direction from zero setting will accurately indicate in amplified manner certain oversize and movement of the pointer in the opposite direction from zero setting will accurately indicate in amplified manner certain undersize. With certain range of sizes or tolerances dictated for factory production, the operator of the apparatus can rapidly classify the parts or bodies discardin or sorting out those which, by meter readings, are indicated as being outside the permissible range of sizes or tolerance.

A modified form'of meter, means is indicated in Fig. 2 which may be substituted for the dial type shown in Fig. 1. It is of the manometer type, comprising a closed well 10 having a body of liquid II therein with the interior connected to and communicating with duct 46 leading from the larger Venturi constriction 3|. A vertical graduated tube I2 has its lower end submerged in liquid 'iI and isadapted for connection to duct 49 leading from the smaller Venturi constriction 32. .Rise or fall of liquid in the graduated tube 72 in accordance with the differential in pressure applied to the column of liquid in the graduated tube and the body '!I thereof in the closed well 19, will accurately give the desired readings during operation of the apparatus shown in Fig. 1. The higher pressure duct 46 leading from the larger Venturi constriction 3I to the chamber in bellows diaphragm 4'! preferably is provided with a restricting means or plate 13 having a restricted orifice or throttling passage I4 therein. The throttling passage 74 will prevent full pressure being applied to the interior of the diaphragm with a surge when the gaging nozzle oriplied to the exterior thereof of course the restricted .orificeor throttling passage will be'em- 8 higher pressure to the exterior, and for similar reasons. v v

A preferred instrument form of the apparatus, which has been constructed for commercial use, is shown in Fig; 3 et seq. That instrument comprises a casing structure I5 having a base I6, a rear wall 11, a top wall I8, side walls ,19 and 89, and a front wall provided with a sloped panel 8! andalower vertical panel 82.

The flexible supply tube 28 is suitably provided on its far end with a fitting 83 for connection to any suitable source of compressed air and extends through an opening 84 in the rear wall 'I'I into the interior of the casingstructure for connection by means of a fitting 85 to the regulator means 2 I. Suitable conduit means 86 makes connection between the downstream'side of regulator means 2| and a pressure gage 81 mounted in the top wall I8 of the casing structure. The pressure regulator mechanism unit 23 has a shaft I24 extending through a hole in a depressed portion or recess 88 in side wall 88 and carries exteriorly of the latter regulator control manual knob 24. A fitting 89 connectsthe downstream side of regulator means 2I to deliver compressed air at a regulated pressure.

The sloping panel 8I of the front wall of the casing structure has a rabbeted hole therein in which is seated a suitable differential pressure gage meter unit 99, with its face exposed to view and its rear end 9| formed by a casing-closing plate 92 extending into the interior of the instrument casing structure I5, as shown in Fig. 4. The Venturi body or block 26 is mounted upon the meter end plate 92 by any suitable means, such as by three stud bolts 9393, each having its head suitably set into a socket 94.

As shown in Fig. 7, the Venturi block 26 of the instrument shown in Figs. 3 to 12 inclusive, preferably has its through bore 28 counterbored at 95 to receive a sleeve 96, which is closed at its larger end by a plug 97 held in position by screw plug 29 threadably mountedinto the larger end of the passage 28. The internal bore 98 of sleeve 96 provides the larger Venturi constriction at SI and has a reduced end 99 fitted in passage 28 and provided with a drill hole I00 to form the smaller Venturi constriction at 32. Beyond the reduced end portion 99 of sleeve 96 passage 28 provides the outlet space or chamber 34 closed-off by the bleed valve structure 30.

The Venturi block 26 is provided with an internally-threaded tapered inlet socket Illl and an internally-threaded tapered outlet socket I92. Socket IDI communicates with the interior of sleeve 96 by means of a drill hole lll3zformed in the block and through the sleeve 96. The outlet socket I82 communicates with the outlet space or chamber 34 by means of a drill hole I84 formed in the block 26. Supply duct or pipe 25 is connected between the outlet compartment of the pressure regulator means and the inlet socket IIJI of the Venturi block 26 respectively by means of fittings 89 and I85. A fitting I66 connects duct or pipe 36 to outlet socket I82 in block 26 and the other end of that duct or pipe is connected by means of fitting I81 to suitable gaging nozzle anchoring means I88 mounted in lower vertical front wall panel 82 of the casing structure I5.

As shown in Figs. 4, 7 and 12, the downstream end of Venturi block 26 iscut back to provide a ployed toadvantage in the duct which feeds the. 1 valve extension I66 seated in-the downstream end 01; xt ma r f e b ehtna a eMagi iiis fleiies vfim one 7 portion 1., The operating teiyreduced endJZ I extending a hole in the recess 8810f side er; washer I 22; located on the u ch-fa e i Wal i0 Theouter end-of shaft I2I s externall thr adeda ec v thereon-manual knob; 68; having; an; interna11y;.-threaded socket therjeirl and,preferably, a; set screw I23-isemployed to prevent relative, rotation therebetween. Thus, {as operating shaft I'IBg is rotated by-conro1.-.k.no 1 5. ne: di ec iom. :i x e n biasingforce of helioa sp ing Hi2 to separate its nner endsfromathe en f Yen r block 25 and to provider-an; outlet: fo h ven ing. W formertby flatting off; at; Ill I: Qfirthfi valve member, extension 1555s.,- Reverse rotation of :control knob. 58 and operatingshaft-illllatherewithwill screw: vexternally\-,I' hr eaded1, portion; I28. out of internallyethreadedi portions-I I11; 3 permitting the biasing. spring I I 2' to snugltheend ofvalve member III] up against the end of Venturi block- 25 toiclose -.oif the; way provided by the fllatting at I I I. Thisvbleednvalvestructure will permit fine adjustment of theirate of flow of air vented from the outlet chamber .or space 36 in the Venturi block 26. it l I I Thelanchoringnmeans I ilfifiorthe gaging nozzle connector preferably. comprises, :as shown in Fig. 6,'a sleeve IZSIs'e'ated in ahole through the panel 83 :andhaving. a circumferentialflange I 26 seated against the-outeriace of the panel. The inner end -ofisleeveelfi extends beyond the inner side of panela, 8 2 and externally threaded to 1 receive a-nu-t- I21 to-ho1d it position; Sleeve IE is provided with an -internal bore I 23 counterbored at oneend to-provide .an internally-threaded tapered socket I2 9-to receive fitting-Iii? on the end of duct or pipe 36 and is counter-bored from the outer end: at I30 slidably toreceivea connector --plugidl -preferably having a circumferential-shoulder 23 -milled fiatted off on diametrically--oppdsite sides at 33!; 331 to fit a correspond-ing'sh'apedpart of bore I30 to prevent; relativerotation, A bayonet: ring I32 is rotatably mounted -on' the outereX-tending end of tliefsleeve I 2 B andcarries pins 133, I33 to be ;received ina circumferential"-groove' I34 in plug I 3I when passed thereto over flats I35, I35, with the ring" IS-Z -then rotatedto the position shownin-Figifle-from-the position shown in Fig. 6; The connector-plug I3I may-be madeintegral or mav-carry directly o the outer end thereof the gaging nozzle means or head 31' or, if desired fthe" passage extending longitudinally through it may be co nmunicatively connected tofthe interior of a flexibleconduit anchored to ed and; engaged into the the plug and extending to a remote location and there provided with the gaging nozzle-head;-

The differential pressure gage-meter im fma y comprise a cylindrical casing member I 36--provided with an internal shoulder I31 to whichis gasketed a partitionplate I 38 anchored by stud bolts 238, and an external shoulder'l 39 to-which is gasketed "and anchoredby any suitable means;

such as st e bone lib- 141}; to the: end plate 9 2. Between the partitionplate" -I 38and erfd plate 92 there is thus formed closed casing chamber I'4I;which corresponds to the chamber in casing 51] of the structure sho'wnin Fig. 1.

The hollow diaphragin- 41 mounted' in cha ber MI and-carries a base structure :which includes a plate I42 gasketedjinto afrecess in the innerfaceof 1 end plate- 92 and -he'ldin position by si',ud bolt I43". The-b'a'sestructure has an extension lld s'eated into a socket 1-45 mine inner face of end plate 92 and the base-structurehas a bore'orpassage l lfi extending there through from chamber I45 intothe interior of diaphragmtl'l.

Withn the meter-casing sleeve I 36 is provided a mechanism housi-ng compartment I 41 between partition plate I38 and dialplate 5I supported structure of which is not. shownother I than as disclosed in principle in Fig. 1,v since "it constitutes no part of-th'e invention claimed herein. Operating pin GIITconnecte'd to theheadotdia phragm'II'I extends througha hole ini partition plate I33 to the interior of the operating mecha nisrnunit I48 and pointer shaft 54 extends from the latter through a central hole in the dial plate 5|. 1 r

An anchoring plate HIS-is provided for holding the meter unit in position in the sloping :rront panel 8|, preferably being arranged to seat in a-circular rabbete'd recess P50 and tob e an'chored by screws I5I--I5I The face plate- I48 isfpro vided with an arcuate-slot I52; preferablyclosed off by transparent panel I53; lheanchoring plate I 49 1 preferably has 'a-centraLstud; I 54 upon which are rotatably mounted a'pair of-segmental gears I55 and I56; Segmental "gear I55 carries an indicator arni I5! to indicateone reference reading or one limit of size or tole'rance ran'ge; e.-g. the limit of plus tolerance for oversi'zed parts, and segmental gear I 561 carries "an indicator arm ['58 to indicate anotherreference read ing or other limit of size or tolerance range; elg. the limit of minus tolerance-for undersized-parts. Anchoring plate I 49- rotatably' carries-control knob I59'for adjustment of theindicator arm I51 and'control knob I60 'for-manua1' adjustmentof indicator arm I58. Thes'e structures are similar, and details thereof 'are'shown in Fig. 1Q,-where it is indicatedthat control knob IE0 is mounted upon a shaft I6 I rotatably supported in a suitable bearing structur'e I52 "mounted through anchoring plate I49 with'the knob fixed to the shaft by set screw II53I The inner end of theshaft' I61 carries fixed thereto as'egmental gear IBII meshed-With segmental gear I56 so "that as the knob I60 is turned, rmeshedsegmental gears I64 and I56 will adjustthe position of rangevindicatorarm I58; As indicated in Fig. 9,

11 Y control knob I59 operates segmental gear I65, which is meshed with segmental gear I55 to adjust the position of indicator arm I51, in a similar manner.

' As shown in Fig. 8, the Venturi block 26 is provided at 3I with bore 45 to align with a hole I61 in sleeve 96. Chamber I45, which is in communication with the interior of diaphragm 41, is connected by a cross bar I68in end plate 92 to a bore I69 therein alignedwith bore 45 in Venturi block 26. The aligned bores 45 and I69 are connected together so that the Venturi constriction of larger diameter at 3I communicates through hole I61 in sleeve 96, bore 45 in Venturi block 26,

bores I69 and I66 in end plate 92, chamber I45 and duct I46 to the interior of hollow diaphragm diaphragm 41 is mounted. The aligned bores 45 and I69 are preferably connected together by being counterbored at I12 to receive a. restricting sleeve I13, having a throttling passage I 14 therein for the surge checking function indicated above.

Theinstrument of Figs. 3 to 12 inclusive is employed in the manner indicated above in connection with the described operation of the mechanism shown in Fig. 1. For example, with the supply tube 26 connected to a suitable source of compressed air regulator manual knob 24 is adjusted so that pressure gage 81 indicates the I desired air supply pressure. The proper gaging nozzle means or head 31 is mounted in fitting I06.

A master or standard part may be brought-into association with the gaging nozzle head 31 and the reference reading of pointer 52 noted. That master or standard port may be of dimensions corresponding to'the smallest that will be tolerated. Another master or standard part of dimensions corresponding to the largest that will be tolerated may then be applied to the gaging nozzle head 31 andthe reference reading of pointer 52 again noted. The two reference read- I ings so obtained define therebetween a section or sector of dial I which indicates the size range for identification of acceptable production parts.

If that sector is too far to one side or other of zero indicia to make conventional reading difficult or impossible, bleed valve control knob 68 is manually rotated to adjust the venting to a rate which will move the reference readings obtainable with 1 the master parts to the desired dial sector, thus the tolerance knobs I59 and I66 then being ma nipulated until the indicator arms I51 and I58 are respectively set to the allowed or dictated maximum plus and minus tolerances.

casethe operator then begins successively gaging the parts by applying each to the gaging nozzle head. 'If pointer 52 remains within the are or sector of dial 5I defined between indicator arms I51 and I58, the operator knows that the gaged part is acceptable. cause pointer 52 to move outside the range of Any parts Whichin gaging that are or sector can be rejected or sorted out. It will thus be understood that the instrument eifectively permits ready alteration and adjustment to any particular set-up employing a parj 41. The smaller Venturi constriction provided by sleeve 96 at 32 is connected via a hole 110 in the I sleeve with bore 48 in Venturi block 26 as shown in Fig. 11. A bore I1I through end plate 92 con- 3 nects bore 48 with casing chamber I4I in which i In either ticular gaging nozzle means or head and that for any given set of conditions the instrument can be readily adjusted to zero setting so that the pointer will operate within a desired dial area.

It will thus be seen that the objects set forth above, among others made apparent from the preceding description, are efiiciently attained and, sincefcertain changes may be made in the above construction and different. embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the followin claims are intended to cover all of the generic and specific features of the invention herein de-- scribed, and all statementsof the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described our invention, what we claim as new and desire to secure by Letters Patent is l. Fluid gage apparatus comprising, in combination, a fluid conduit means, a source of fluid under predetermined pressure connected thereto, a Venturi means in said conduit having two sea tions of different cross sectional areas through which the fluid is adapted successively to ad-- vance, a gaging nozzle connected to said conduit means to check the dimensions of articles, and an indicator connected to each of said Venturi sections to respond to the differential pressures thereof in accordance with the respective fluid velocities and thereby to check the dimensions of said articles.

2. Fluid gage apparatus comprising, in combination, Venturi conduit means having a fluid inlet side, a closed outlet space and an intervening passage provided with a pair of Venturi constrictions of different diameters, means to conduct fluid from the outlet space to gaging nozzle means, differential pressure gage meter means operable by a differential in fluid pressure, means to conduct fluid pressures from said pair of Venturi constrictions to said gage meter means to apply to the latter differentials in pressure existing at the constrictions, means providing a relief passage for venting the closed outlet space to atmosphere, and an adjustable manual bleed valve in the relief passage to control rate of venting for adjustment of said meter means to desired setting.

3. A self-contained fluid gage apparatus comprising, in combination, a casing structure having its interior in'communication with the atmosphere, a fluid supply conduit extending through an aperture in a wall thereof to the interior of said casing structure, adifferential pressure gage meter mounted in said casing strucof said casing structure for removable reception of gaging nozzle means, other conduit means in said casing structure connecting said fitting to the downstream side of said body, means providing a relief passage in said body for venting the downstream side thereof to the interior of said casing structure, a bleed valve in the relief passage to control rate of venting for adjustment of the meter indicator to zero setting, and a manual control mounted on one side of said casing structure and exposed exteriorly thereof and extending into the interior of the latter to connection with said bleed valve.

4. A self-contained fluid gage apparatus comprising, in combination, a casing structure having its interior in communication with the atmosphere, a fluid supply conduit extending through an aperture in a wall thereof to the interior of said casing structure, a differential pressure gage meter mounted in said casing structure with a dial thereof exposed to view on the casing face and having a movable indicator and indicator-operating means including a diaphragm, a Venturi block mounted in said casing structure on the rear of said meter and having a stepped passage extending therethrough capped off at one end, bleed valve structure closing off the other end of said stepped passage, the stepped passage providing a pair of Venturi constrictions with the one nearest the bleed valve structure being of lesser crosssectional dimension, said Venturi block being provided with an inlet bore leading to the stepped passage at a point between the capped end thereof and the Venturi constriction of larger crosssectional dimension, said Venturi block being provided with an outlet bore connected to the stepped passage between the bleed valve structure and the Venturi constriction of smaller cross-sectiona1 dimension, said meter and Venturi block being connecting the Venturi constrictions to opposite sides of the meter diaphragm, conduit means in said casing structure connecting said supply conduit to the inlet bore in said Venturi block, a fitting on the front of said casing structure for removable reception of gaging nozzle means, other conduit means in said casing structure connecting to said fitting the outlet bore or said Venturi block, and a manual control mounted on one side of said casing structure and exposed exteriorly thereof and extending into the interior of the latter to connection with the bleed valve closing oif the downstream end of the stepped passage extending through the Venturi block, said bleed valve being adapted to provide for controlled rate of venting of fluid from the system downstream of the Venturi constrictions and upstream of gaging nozzle means for adjustment of the meter indicator to zero setting.

CLIFFORD STEAD. FRANKLIN MEYER, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,641,295 Schroeder Sept. 6, 1927 1,870,058 Levine Aug. 2, 1932 1,940,921 Smith Dec, 26, 1933 1,971,271 Mennesson Aug. 21, 1934 2,177,244 Ciamberlini Oct. 24, 1939 2,185,971 Achtel et a1 Jan. 2, 1940 2,360,705 Moore Oct. 17, 1944 2,446,632 Cahill et a1. Aug. 10, 1948 2,457,401 Rupley Dec. 28, 1948 OTHER REFERENCES Publication "New-Matic Measuring Machines, Merz Engineering Co., Indianapolis, Ind., May 1947, page 5. 

